PlainCities

Counties · Montana

Counties of Montana

Montana has 56 counties. Yellowstone County is the largest with 172,692 residents in 2025. 36 of the 56 gained residents between 2020 and 2025 by the Census Bureau's estimates.

What counties are in Montana?

Sorted by the 2025 population estimate; sort by any column.

Counties of Montana: 2025 estimate, change since 2020, ACS 2020-2024 5-year estimates
Yellowstone County172,692+4.8%1336$76,570$349,500
Gallatin County128,740+8.2%1926$93,528$667,600
Missoula County123,513+4.7%1729$75,598$472,100
Flathead County115,429+10.6%2432$73,925$535,500
Cascade County85,029+0.7%2425$67,690$265,300
Lewis and Clark County75,331+6.1%1817$78,237$393,500
Ravalli County48,582+10.0%1013$71,283$476,600
Silver Bow County36,118+2.8%29$61,754$255,200
Lake County33,392+7.2%2410$63,360$421,800
Lincoln County22,328+13.5%156$47,143$296,500
Park County18,214+5.9%146$70,047$467,500
Hill County16,167−0.7%226$52,798$202,600
Sanders County14,062+13.4%144$57,476$359,000
Glacier County13,463−2.3%184$46,875$165,100
Jefferson County13,329+10.3%103$95,490$446,900
Big Horn County12,752−2.8%105$58,750$143,400
Custer County12,034+1.5%26$70,605$219,100
Fergus County11,825+3.3%173$63,706$236,100
Carbon County11,466+9.5%155$80,261$420,800
Richland County11,377−1.0%55$73,084$263,000
Roosevelt County10,242−5.2%63$57,063$118,800
Beaverhead County10,043+7.2%123$61,268$308,300
Madison County10,026+16.3%144$75,250$470,100
Deer Lodge County9,709+3.0%13$57,527$231,700
Stillwater County9,445+5.4%73$84,732$405,800
Dawson County8,692−2.8%53$71,334$185,300
Broadwater County8,493+25.4%72$70,374$426,600
Rosebud County8,253−1.0%64$49,914$182,400
Valley County7,385−2.6%73$71,695$198,400
Powell County7,157+3.1%82$66,923$306,500
Blaine County6,860−2.6%114$64,813$155,500
Teton County6,496+4.3%93$70,430$264,000
Pondera County6,072+2.8%102$52,338$206,100
Chouteau County5,865−0.8%132$58,218$207,800
Musselshell County5,582+17.9%72$58,920$235,000
Toole County5,211+4.8%73$57,731$218,400
Mineral County5,185+14.5%82$63,450$364,300
Phillips County4,203−0.3%91$53,417$197,600
Sweet Grass County3,762+2.2%21$77,000$330,100
Granite County3,658+10.7%42$59,265$352,700
Sheridan County3,436−3.1%82$70,147$124,000
Fallon County2,959−3.0%21$76,250$244,800
Judith Basin County2,162+7.0%91$59,000$238,300
Meagher County2,137+11.0%31$71,932$259,800
Wheatland County2,100+1.4%71$49,489$180,800
Liberty County1,957−0.1%61$57,857$169,100
Powder River County1,781+5.1%21$67,045$192,100
McCone County1,720−0.5%41$69,375$211,600
Daniels County1,612−2.5%41$55,625$184,800
Carter County1,383−2.1%21$54,167$199,200
Garfield County1,148−1.9%11$69,583$169,900
Prairie County1,112+1.6%21$51,250$165,700
Wibaux County885−5.5%11$67,462$98,600
Golden Valley County844+2.2%31$58,333$212,200
Treasure County728−4.2%11$67,917$230,300
Petroleum County548+10.0%11$60,208$201,400

Source: PEP Vintage 2025 (CO-EST2025); American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Census population estimates

How these figures are made: methodology and release checks · reading a margin of error · every state · corrections